The present invention relates to a window glass of a vehicle, which is adapted to prevent noise caused by various kinds of electrical components in the vehicle from being transmitted to a rod-shaped roof antenna (RMA, Roof Mounted Antenna) mounted on an upper rear portion of the roof of the vehicle.
In recent years, a glass antenna which is formed by printing or burning conducting lines of conductive ceramic paste on a surface of a window glass, has been used as a vehicle antenna, and the use of this glass antenna has spread. On the other hand, also a rod-shaped roof antenna mounted on a roof of the vehicle is still used, and often used as diversity reception with the glass antenna.
Nowadays, as electronic technology progresses further, a multitude of electrical components are used in the vehicle. However, some of these electrical components produce noise, and the noise acts on the antenna such as the roof antenna. As a result, there arises a problem that receiving performance of FM radio wave which the roof antenna receives is deteriorated by the noise. And such case has arisen quite often.
For the above problem, the electrical component producing the noise is shielded by conductive material or a conductive body in order to minimize the occurrence of the noise or to reduce the noise to zero. Further, to suppress the occurrence of the noise from the electrical components, measures in which a vehicle body is grounded etc. are taken. However, despite taking these measures, there is a case where the noise cannot be reduced.
For this reason, in order to prevent the noise produced by such electrical components from being transmitted to a side of the antenna, various manners have been proposed.
For instance, one such manner has been disclosed in Japanese Patent Provisional Publication No. 2004-260504 (hereinafter is referred to as “JP2004-260504”). JP2004-260504 has disclosed an antenna structure of the vehicle, which has antenna lines disposed in a head space of an electric heating rear defogger that is provided on a rear window glass of the vehicle. More specifically, in a space between the rear defogger and the antenna lines, a shield line which electromagnetically isolates the rear defogger that is a noise radiation source, is provided.